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<head>
  <title>Draggable Link Labels That Stay On Path</title>
  <!-- Copyright 1998-2021 by Northwoods Software Corporation. -->
  <meta name="description" content="TypeScript: This variation on the LinkLabelDraggingTool extension restricts link labels to stay on the link's route while the user is dragging it." />
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  <script src="../samples/assets/require.js"></script>
  <script src="../assets/js/goSamples.js"></script>
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  <script id="code">
    function init() {
      require(["LinkLabelOnPathDraggingScript"], function(app) {
        app.init();
      });
    }
  </script>
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<body onload="init()">
  <div id="sample">
    <div id="myDiagramDiv" style="background-color: whitesmoke; border: solid 1px black; width: 100%; height: 600px"></div>
    <p>
      This sample demonstrates a custom Tool, LinkLabelOnPathDraggingTool, that allows the user to drag the label of a Link, but
      that keeps the label exactly on the path of the link. The tool is defined at <a href="LinkLabelOnPathDraggingTool.ts">LinkLabelOnPathDraggingTool.ts</a>.
    </p>
    <p>
      The label on the link can be any arbitrarily complex object.
      It is positioned by the <a>GraphObject.segmentIndex</a> and <a>GraphObject.segmentFraction</a> properties.
      The segmentIndex is set to NaN such that the whole link path acts as the segment, and the segmentFraction is set by the LinkLabelOnPathDraggingTool.
      A two-way data binding on segmentFraction automatically remembers any modified value on the link data object in the model.
    </p>
    <p>
      The tool is derived from a similar tool, <a href="LinkLabelDraggingTool.ts">LinkLabelDraggingTool.ts</a>, that allows
      the user to drag the label in any direction from the mid-point of the Link path.
    </p>
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